A creature that lived 250 million years ago with elephant-like tusks and a “turtle-like beak” is the oldest-known creature to hibernate in order to survive, a newly published study has found.
The research, published in the scientific journal Communications Biology, notes that Lystrosaurus was able to slow its metabolism, going through a state of torpor (hibernation) based on fossilized evidence.
“Animals that live at or near the poles have always had to cope with the more extreme environments present there,” said the study’s lead author Megan Whitney, in a statement. “These preliminary findings indicate that entering into a hibernation-like state is not a relatively new type of adaptation. It is an ancient one.”
The researchers looked at cross-sections of six Lystrosaurus from Antarctica and four from South Africa and compared them. They saw there were similar growth patterns in dentine, but the ones from Antarctica had “closely-spaced, thick rings,” which the researchers believe was due to prolonged stress.
“The closest analog we can find to the ‘stress marks’ that we observed in Antarctic Lystrosaurus tusks are stress marks in teeth associated with hibernation in certain modern animals,” Whitney added.
Lystrosaurus could grow up to 8 feet long and the genus managed to survive the planet’s largest mass extinction event, approximately 252 million years ago, LiveScience reported.
The researchers aren’t 100% certain Lystrosaurus needed true hibernation, as the stress marks seen in the Antarctican Lystrosaurus could be from another type of torpor.
However, given their findings, the researchers believe Lystrosaurus was warm-blooded and did shut down for periods of time.
“Cold-blooded animals often shut down their metabolism entirely during a tough season, but many endothermic or ‘warm-blooded’ animals that hibernate frequently reactivate their metabolism during the hibernation period,” Whitney explained. “What we observed in the Antarctic Lystrosaurus tusks fits a pattern of small metabolic ‘reactivation events’ during a period of stress, which is most similar to what we see in warm-blooded hibernators today.”